Chloroplast Lab Report

And finally into test tube 3, I pipetted 1.0 ml turnip extract and 4.0 ml of water. The contents of test tube 1 was poured into a spectrometer tube and labeled it “B” for blank. “B” tube was now inserted it into the spectrometer. An adjustment to the control knob was made to zero the absorbance reading on the spectrometer since one cannot continue the experiment if the spectrometer is not zeroed. A combination of two people and a stop watch was now needed to not only record the time of the reaction, but to mix the reagents in a precise and accurate manner. As my partner recorded the time, I quickly poured tube 3 into tube 2. I then poured tube 2 into the experiment spectrometer tube labeled “E” and inserted it into the spectrometer. A partner then recorded the absorbance reading for every 20 seconds for a total of 120 seconds. After the experiment, a brown color in the tube should be observed to indicate the reaction was carried out. Using sterile techniques, any excess liquid left was disposed

The purpose of this experiment is to determine the maximum absorbance of fast green, and the chlorophylls, also in the case of fast green create a concentration curve to determine an unknown substance. Each test will use the spectrophotometer.

There are many procedures during this lab and many materials needed for an accurate analysis of data. First, fill a 100 mL graduated cylinder with 50 mL of water. Add 25 germinating peas and determine the amount of water that is displaced. Record this volume of the 25 germinating peas, then remove the peas and put those peas on a paper towel. They will be used for the first respirometer. Next, refill the graduated cylinder with 50 mL of water and add 25 non-germinating peas to it. Add glass beads to the graduated cylinder until the volume is the same to that of germinating peas. Remove the beads and peas and put on a paper towel. They will be used in respirometer 2. Now, the graduated cylinder was filled once again, determine how many glass beads will be require to reach the same volume of the germinating peas. Remove the beads and they will be used in respirometer 3. Then repeat the procedures used above to prepare a second set of germinating peas, dry peas and beads, and beads to be used in respirometers 4,5,and 6, the only difference is the temperature of the water.

14) Obtain the unboiled chloroplast suspension, mix, and transfer 3 drops to cuvette 3. Immediately cover and mix cuvette 3. Insert it into the spectrophotometer's sample holder, read the percentage transmittance, and record it in Table 4.4. Replace cuvette 3 into the incubation test tube rack. Take and record additional readings at 5, 10, and 15 minutes. Mix the cuvette's contents just prior to each readings. Remember to use cuvtte 1 occasionally to check and adjust the spectrophotometer to 100% transmittance.

The turnip extract that will be used has been prepared so that it has peroxidase as the enzyme, so .5 grams of turnip were added to 200 ml of water. The rest of the substances do not need further preparation.

The initial experiment was a success. As our treatment group spent more and more time under the lights, the absorbance rate continues to decrease toward zero. Once our 30 minutes were up, the absorbance rate in each tube was significantly lower than at the start of our experiment. In contrast the two control groups did significantly lower the absorbance. Each control lacked one of the vital aspects of photosynthesis, one being light, and the other being chloroplast. Neither of the control groups (Control 1 or 2) showed any signs of photosynthesis. Control 1 was exposed to light, but contained no photosynthetic organelles thus the absorbance throughout the 30 minutes varied minimally, mostly staying stagnant. Control two which contained chloroplast but was not exposed to any light failed to lower the absorbance at all and in fact increased the absorbance over the 30 minutes. However, the treatment group contained both and ultimately performed photosynthesis as we expect therefore, confirming our assumption that chloroplast were the organelles required for photosynthesis in plants and that light is required to perform said photosynthesis. The treatment group, containing both the chloroplast and being exposed to light provided evidence that photosynthesis was taking place as the absorbance lowered at each 10-minute interval. Having a less absorbance would be desired because as DCIP became reduced we would expect the solution to become more and more clear, thus less

Finally, the test tubes were placed in the the rack and we recorded the color of the solution for day one in table

L-broth, or a sterile growth media, is dispensed at 35mL into a sterile 125mL flask. Small volumes of E. coli are added to each flask. Each flask is then placed into three separate shaking incubators set for specific temperatures of twenty-five degrees Celsius, thirty degrees Celsius, thirty-seven degrees Celsius, and forty-two degrees Celsius. The incubators are all set to the same shaking speed of 125 rotations per minute. A Spectrophotometer is also used to estimate the density of the culture. A spectrophotometer is a device that transmits a beam of light through space toward a light sensor (Trzepacz et. al). The spectrophotometer measures the density of the culture by measuring the amount of light that travels through to the sensor. The spectrophotometer is set to transmit light at a 600nm wavelength. In order to do so, 1.0 mL of the culture is transferred with a plastic pipet into a cuvette. To remove bubbles from the culture, the bottom of the cuvette is gently tapped. The cuvette is then placed into the spectrophotometer. While the 1.0 mL is being measured, the rest of the E. Coli culture is in the shaking incubators. Every 20 minutes, a new 1.0 mL sample is taken from the E. Coli culture in the incubators and is measured in the spectrophotometer. Four to five absorbance readings were collected during each lab period throughout the

This experiment was performed using the procedure from the Photosynthesis in Leaf Disks Lab. First using a #3

The purpose of this lab is to understand the process of photosynthesis and how sunlight effect has on it. To prove that in order for photosynthesis to happen light is needed, and to see if temperature has an effect on how fast or how slow photosynthesis happens.

Chloroplast Activity in Cells Questions & Hypothesis In wet lab two, our group decided to use the cells of broccoli to perform our experiments. Part one of our experiment was meant to focus on the presence of chloroplasts in solutions of isolation buffer and DCIP. Our group was attempting to find which cell fractionate solution contained the highest amount of broccoli chloroplasts after three separate suspensions were made (P1, P2, S2). The presence of chloroplasts in the solution is directly related to a decrease in measured absorption of 600 nm wavelengths by a spectrometer (Leicht and McAllister 85).

With this, the normal rate of absorbance could be measure and compared to those that contained chelating agents in order to see if the ion that was taken away by the chelating agent was needed. 5 mL of dH2O was added to Tube 5. Tube 5 was the calibration tube considering it contained nothing but distilled water. All of the substances were added to the tubes by pipettes in order to accurately measure the amount of substances. Whenever the chelating agents (the PTU, Citric Acid, and EDTA) were added to the tubes, the agents were taken from the top of the solution by a pipette in order to avoid the parts of the solution that had settled.

The photosynthesis lab is comprised of three short experiments. These experiments showed how to understand and apply the absorbance spectrum and which colors and wavelengths correspond to visible light. In order to fully understand this absorbance spectrum and how to apply it, we initially prepared a substance comprised of acetone, a large spinach leaf and petroleum ether and measured its absorbance in the spectrophotometer. This showed us what wavelengths corresponded to the most absorption of the spinach leaf. It is understood that the least amount of absorbance should occur after 500 nm and the lower the number, the lower the absorbency. Thus, the 700 ranges is the very least amount of absorbency and the results showed us that the lowest amount of absorbance was around 740nm, which is an accurate, representation of this solution. Next, to understand what wavelengths of light drive the light reactions you can visibly see in photosynthesis, we used CMS in a variety of tubes and measured its absorbency under white light, no light, and colored filters such as red and green. We then used the chlorophyll extract we originally prepared and painted this on a chromatography strip. We measured the band distances to find out the number of pigments in the spinach leaf. These processes helped emphasize how the chloroplast pigment extract and chloroplast membrane suspension have different functional capabilities and how photosynthesis works.

After wearing the gloves we obtained a chromatography vial from professor and label it with my and my peer initials. We dried up the chromatography vial in fume hood and added 1 ml of chromatography solvent to the vial. Then we took a chromatography strip and measure it 1.5 cm with ruler from one end of the strip and drew a line with pencil we cut two small pieces below the pencil line to form a pointed end. We applied spinach on the strip using quarter to rub the spinach leaf on the line that we drew on the strip and put it into the chromatography vial and placed that in fume hood. We observed as the solvent was moving up the chromatography strip by capillary action. When the solvent was reached approximately 1 cm from the top of the strip then we removed the cap from the vial. We took out the strip from the vial using forceps and marked up the location of the solvent front because it evaporates quickly. We measure out the distance as well as the pigment in order to find out the rf value. Moreover we compared rf values to the one in reference list in order to identify the

The following procedure dealt with a chromatogram. The materials needed are: a pencil, safety goggles, scissors, chromatography paper strip, capillary tube, spinach plant pigment extract, test tube, cork stopper, graduated cylinder, chromatography solvent (alternative isopropyl alcohol), metric ruler, stopwatch or clock with a secondhand, hook/fashioned paperclip, paper towels, test tube rack, and mortar and pestle. First we obtained a strip of chromatography paper and cut it so it would fit inside a test tube (with it barely touching the bottom of the tube). Also, when touching the strip, touch the sides only. Then we attached (firmly) the top of the strip to a hook (or fashioned paperclip at bottom of the cork stopper). Make sure it fits in the test tube. Next we used the pencil to draw a faint line across the strip two centimeters from the bottom tip of the strip. We placed the cork and strip in place, and we put a mark on the test tube one centimeter below the top of the stopper.